We identified two informative polymorphisms in the transcribed 3' untranslated region of the tumor necrosis factor receptor 2 (TNFR2) gene using the polymerase chain reaction (PCR) with the single-strand conformation polymorphism (SSCP) technique. These polymorphisms demonstrated Mendelian inheritance and were useful for linkage analysis. TNFR2 was very closely linked to the pronatriodilatin gene (PND), and the TNFR2 SSCP polymorphisms were much more informative than the restriction fragment length polymorphisms currently available for the PND locus. In addition, we have demonstrated that genotyping could be performed with DNA obtained from paraffin-embedded tissue.